This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Finn, M. W. Articles by Tabita, F. R. Search for Related Content PubMed PubMed Citation Articles by Finn, M. W. Articles by Tabita, F. R.

Modified Pathway To Synthesize Ribulose 1,5-Bisphosphate in Methanogenic Archaea

Department of Microbiology,¹ Plant Molecular Biology/Biotechnology Program, The Ohio State University, Columbus Ohio²

Received 17 March 2004/ Accepted 29 June 2004

Several sequencing projects unexpectedly uncovered the presence of genes that encode ribulose 1,5-bisphosphate (RuBP) carboxylase/oxygenase (RubisCO) in anaerobic archaea. RubisCO is the key enzyme of the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway, a scheme that does not appear to contribute greatly, if at all, to net CO₂ assimilation in these organisms. Recombinant forms of the archaeal enzymes do, however, catalyze a bona fide RuBP-dependent CO₂ fixation reaction, and it was recently shown that Methanocaldococcus (Methanococcus) jannaschii and other anaerobic archaea synthesize catalytically active RubisCO in vivo. To complete the CBB pathway, there is a need for an enzyme, i.e., phosphoribulokinase (PRK), to catalyze the formation of RuBP, the substrate for the RubisCO reaction. Homology searches, as well as direct enzymatic assays with M. jannaschii, failed to reveal the presence of PRK. The apparent lack of PRK raised the possibility that either there is an alternative pathway to generate RuBP or RubisCO might use an alternative substrate in vivo. In the present study, direct enzymatic assays performed with alternative substrates and extracts of M. jannsachii provided evidence for a previously uncharacterized pathway for RuBP synthesis from 5-phospho-D-ribose-1-pyrophosphate (PRPP) in M. jannaschii and other methanogenic archaea. Proteins and genes involved in the catalytic conversion of PRPP to RuBP were identified in M. jannaschii (Mj0601) and Methanosarcina acetivorans (Ma2851), and recombinant Ma2851 was active in extracts of Escherichia coli. Thus, in this work we identified a novel means to synthesize the CO₂ acceptor and substrate for RubisCO in the absence of a detectable kinase, such as PRK. We suggest that the conversion of PRPP to RuBP might be an evolutional link between purine recycling pathways and the CBB scheme.

This article has been cited by other articles:

• Badger, M. R., Bek, E. J. (2008). Multiple Rubisco forms in proteobacteria: their functional significance in relation to CO2 acquisition by the CBB cycle. J Exp Bot 0: erm297v1-erm297 [Abstract] [Full Text]  
• Tabita, F. R., Hanson, T. E., Li, H., Satagopan, S., Singh, J., Chan, S. (2007). Function, Structure, and Evolution of the RubisCO-Like Proteins and Their RubisCO Homologs. Microbiol. Mol. Biol. Rev. 71: 576-599 [Abstract] [Full Text]  
• Sato, T., Atomi, H., Imanaka, T. (2007). Archaeal Type III RuBisCOs Function in a Pathway for AMP Metabolism. Science 315: 1003-1006 [Abstract] [Full Text]  
• Kreel, N. E., Tabita, F. R. (2007). Substitutions at Methionine 295 of Archaeoglobus fulgidus Ribulose-1,5-bisphosphate Carboxylase/Oxygenase Affect Oxygen Binding and CO2/O2 Specificity. J. Biol. Chem. 282: 1341-1351 [Abstract] [Full Text]  
• Raymond, J. (2005). The Evolution of Biological Carbon and Nitrogen Cycling--a Genomic Perspective. Reviews in Mineralogy and Geochemistry 59: 211-231 [Full Text]